1. Field of the Invention
The present invention is directed to an improved biopsy guide device and a method used for positioning the biopsy guide device in a subcutaneous target for percutaneous biopsy. More specifically, the present invention is directed to an improved needle biopsy guide device and method of use thereof in obtaining multiple biopsies within a target area.
2. Description of the Prior Art
It has become common to take samples of inner tissues from men and animals with devices which pass through the skin. Tissue samples taken in this manner are used to diagnose various diseases such as cancer without resorting to open surgery. Guidance by medical imaging becomes useful when targets are not adequately localized by external palpation. For example, a great importance is placed on the use of mammography for the early diagnosis of breast cancer. Early intervention appears to alter the outcome of the disease. Mammography screening detects small suspicious areas within the breast before they are palpable by a physician or by the patient. However, for most of these suspicious areas, mammography cannot distinguish malignant tissue from benign tissue. This shortcoming of mammography often precipitates a biopsy. Most suspicious abnormalities are benign if biopsied. The patient with a suspicious area on a mammogram must decide between the worry of waiting and watching versus the pain, disfigurement and cost of open surgical biopsy. A by-product of mammography, this problem is common and costly to society in health care dollars, suffering and litigation.
The method for making a definitive diagnosis of breast cancer is by microscopic examination of the suspect tissue. Accurate techniques less costly than open surgical biopsy to obtain samples of suspicious tissue for microscopic examination are desired. For example, core needle biopsy devices which pass through the skin guided by stereotactic mammography or ultrasound can accurately sample suspicious targets and have become popular alternatives to open biopsy. Recent studies suggest that tissue cores obtained using a stereotactic mammographically guided biopsy with large 14 gauge needles are equal in microscopic diagnostic accuracy to open surgical biopsy. However, as many as 5 to 15 biopsy specimens are currently considered usual and necessary for large core needle biopsies of mammary glands.
Alternatively, breast sonography can be used for large needle core biopsy guidance instead of stereotactic mammography in 25-35% of suspicious breast abnormalities. Both stereotactic mammography and breast sonography are being commercialized with vigor as a replacement for open surgical biopsy, touting reductions in cost, waiting period and breast disfigurement.
Stereotactic mammographic guided biopsy requires costly equipment and costly floor space which are new expenses. The invention herein eliminates the need for stereo guidance.
Another problem with stereotactic mammography is the possibility of needle track seeding with malignant cells. Needle track seeding with malignant cells after undergoing only 5 large stereotactic needle biopsies has been documented histologically in a mammary gland which was later surgically removed for cancer (Harter L. P. et al., Radiology 1992; 185:713-714).
Most stereotactic biopsy units operate preferentially with the needle perpendicular to and directed toward a compression paddle or film holder. This is the shortest dimension of a breast flattened by compression paddles. Unfortunately, small breasts or targets near the deep skin surface run the risk of biopsy needle penetration of the far side skin causing impact damage to equipment (bucky bashing). Short throw biopsy needles can be employed but are known to provide inferior tissue specimens compared to long-throw needles. Also, a strict long-term stable relationship is required between the patient and the needle. Also, patient movement between stereotactic calculations and needle placements send the needle to a former target location. The intrinsic mobility of suspicious targets in soft breast tissue result in glancing tangential target misses because the target moves off to the side during needle thrust.
Percutaneous cannula guides have been used to guide biopsy devices to the target tissue for repeated sampling. These are coaxial in design. The cannula goes to or toward the abnormality, but not through it. The biopsy needle passes through the guide cannula. Coaxial guide cannulas present only one trajectory through the tissue target until redirected by new imaging guidance. Coaxial devices for biopsy do not internally immobilize the target. Since coaxial devices provide only alignment to the target, patient motion, cannula motion or tangent target displacement can result in a misdirected biopsy.
Coaxial external needle guides, some employing cannulas, have been used to hold and guide percutaneous breast biopsy needles (Siczek et al. U.S. Pat. No. 5,078,142, and Aarnio et al. U.S. Pat. No. 5,107,843). Most of those external guides require stereotactic positioning. One such device includes a combination of external and percutaneous guides (Teubner et al., U.S. Pat. No. 5,219,351). Part of Teubner's stereotactic guided device is called a needle in his patent, but it is a percutaneous guide cannula. It is coaxial and stereotactic, and suffers from most of the drawbacks of such method. Teubner et al. solve one of the stereotactic biopsy problems (difficulties with targets in thin breasts or those lying near the posterior skin surface) by allowing the biopsy needle the freedom to angle away from perpendicular-to-image-receptor and offer improved choice of puncture site. Teubner's coaxial stereotactic guided device is expensive and patient access to it is limited. The external guide devices are distant from the target and subject to needle trajectory deflection and to patient or target motion.
Such disadvantages are also true for the multi-lumen biopsy cannula designed by Zatloukal et al. (U.S. Pat. No. 4,850,373). Zatloukal retains coaxial design, presenting only one trajectory through target tissue for repeated biopsies unless the whole cannula is repositioned. The multi-lumen biopsy cannula of Zatloukal et al. has a circular cross-section outer cannula that contains a close fitting inner biopsy cannula with its circular cross section flattened on one side less than 1/3 its maximal diameter producing a 1/3 moon-shaped second lumen between the inner and outer cannulas. The quarter-moon-shaped extra lumen is not designed for the purpose of the transmission of guide pins, fixation wires or other sampling devices. The extra lumen was designed for the injection of substances such as blood coagulation substances, vasoactive drugs and the like to the target site. The cannulas are coaxial but are not joined. One is free to rotate inside the other, thereby failing to provide a predictable orbit for the biopsy channel around an axle mandrel in the target. Thus, the coaxial cannulas do not allow the biopsy channel to appose a new locus on the target as in the present invention later described.
Multiple cannulas or tandem multichannel devices, joined side-to-side inside and outside the body, where target guidance and internal fixation is the purpose of one cannula while the other cannula is used for biopsy, as in the present invention, have not appeared in the medical or patent literature.
Kambin (U.S. Pat. No. 5,395,317) discloses a device with tandem channels and a mandrel guidance. Kambin employs one channel for coaxial mandrel guidance and use of the same channel for intervertebral disectomy after removing the mandrel during the surgical procedure. A tandem channel for endoscopy follows the first channel and is not permanently joined. Kambin employs a jig as a means to join and to guide the second tandem cannula alongside the first image-guided cannula. The joining means jig is entirely external to the body. The joining means jig in Kambin does not provide a solid permanent joining, and the joining means does not penetrate into subcutaneous tissues and therefore rotation or withdrawal or insertion forces applied to one cannula do not predict the behavior of the movement of the other cannula. Also, external forces on the proximal ends of both cannulas do not predict the behaviors of the internal distal ends of both cannulas.
The Biopsys Mammotome (U.S. Pat. No. 5,649,547) is a tandem joined multiple channel biopsy device. The Biopsys Mammotome uses one channel for suction and one channel for mechanized biopsy, relies on external positioning devices and not internal fixation devices, requires strict breast immobilization and stereotactic guidance or sonographic guidance. The patent alleges that the device rotates about its biopsy channel. (see also Biopsys Mammotome, Mark Ritchart, John Wardle, Fred Burbank MD et al. Biopsys Medical, Inc. Biopsys Medical, Inc (Premier Laser), 3 Morgan, Irvine, Calif. 92718).
Kornberg (U.S. Pat. No. 5,111,828) shows guidance over a mandrel, orthogonal imaging and target anchoring. However, closer inspection discloses a percutaneous excisional breast biopsy device having the following deficiencies: (1) non-removable anchor, (2) a slender hook-wire which should not be followed forward over (manufacturer warnings; existing litigation related to post-surgical retained hook wire); (3) one time biopsy; (4) orthogonal images all completed before device insertion; (5) guide sleeve and hook wire removed by single biopsy; (6) excisional biopsy; and (7) unsuitable for lesions over 20 mm.
Stylets, wires, pins and mandrels have been used as guide devices for biopsy. Previous to Kambin (U.S. Pat. No. 5,395,317) such guide devices have been a part of coaxial systems. The mandrel is removed after a cannula device has been positioned over it, since the cannula would be difficult or impossible to use while the guide mandrel occupies its channel. Coaxial guide mandrels are good for only one tissue sample. Coaxial guide mandrels must be repositioned by using medical imaging if additional mandrel-guided samples are desired. Kambin also withdraws his guide mandrel because he has other uses for both of his channels. An ingenious large "stylet", designed with a central channel to follow over a guide mandrel, shown in the breast biopsy device of Kornberg et al. (U.S. Pat. No. 5,111,828) is coaxial, but can only obtain one biopsy with each guide placement. The size of the Kornberg device required for excision makes his procedure painful and is as difficult as open biopsy for larger targets, especially in patients with tough, fibrous breasts.
Although there are a number of biopsy devices in the medical and surgical industry, there is still a need for a biopsy guide device that can provide multiple biopsies from a subcutaneous target area.